Method for calibrating temperature in chemical vapor deposition

ABSTRACT

In a method for semiconductor processing, a semiconductor substrate is provided. The semiconductor substrate defines at least one first trench therein. The at least one first trench has a first depth (d1). A coating layer is deposited onto the semiconductor substrate using at least one precursor under a setting for a processing temperature (T). The coating layer defines at least one second trench having a second depth (d2) above the at least one first trench. A depth parameter (t) the second depth (d2) relative to the first depth (d1) is determined. The processing temperature (T) is then determined based on a pre-determined standard reference curve comprising a plurality of references depth parameters in a first range as a function of a plurality of reference processing temperatures in a second range.

PRIORITY CLAIM AND CROSS-REFERENCE

This application claims the benefit of U.S. Provisional Application No.62/538,336, filed Jul. 28, 2017, which application is expresslyincorporated by reference herein in its entirety.

BACKGROUND

As semiconductor devices are scaled to smaller sizes, new materials andconcepts are being considered to meet advanced performance targets.Processing conditions at each step are also extremely important forcontrolling the quality of the semiconductor devices.

Chemical vapor deposition (CVD) is a process for forming stable solidsby decomposition of gaseous chemical using heat, plasma, ultraviolet, orother energy sources, or combinations thereof. Reactant gases are passedover a wafer, causing CVD of a thin layer of the reactant material onthe wafer. For example, epitaxial growth of silicon can be achieved byCVD using heat as the energy source for decomposing one or more gaseouschemicals. The temperature in the CVD process can affect growth rate andmorphology of the deposited product. Various process conditions, e.g.temperature uniformity and reactant gas distribution, must be carefullycontrolled to ensure high quality of the deposited layers and resultingsemiconductor devices.

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects of the present disclosure are best understood from the followingdetailed description when read with the accompanying figures. It isnoted that, in accordance with the standard practice in the industry,various features are not drawn to scale. In fact, the dimensions of thevarious features may be arbitrarily increased or reduced for clarity ofdiscussion. Like reference numerals denote like features throughoutspecification and drawings.

FIG. 1 is a cross-sectional view illustrating a portion of an exemplarydevice comprising a coating layer disposed on a semiconductor substratein some embodiments.

FIG. 2A is a flow chart illustrating an exemplary method for calibratingand adjusting temperature in a processing chamber for making a coatinglayer in accordance with some embodiments

FIG. 2B is a flow chart illustrating an exemplary method for generatinga pre-determined standard reference curve in accordance with someembodiments.

FIG. 3 is a cross-sectional view illustrating a portion of an exemplarysemiconductor substrate defining at least one trench therein in someembodiments.

FIG. 4 is a cross-sectional view illustrating an exemplary structurewith a coating layer disposed on the semiconductor substrate of FIG. 3in accordance with some embodiments.

FIG. 5 is a plan view illustrating exemplary locations of trenches on asemiconductor substrate in some embodiments.

FIG. 6 is a plan view illustrating a plurality of trenches on asemiconductor substrate in some embodiments.

FIG. 7 is a cross-sectional view illustrating the exemplary structure ofFIG. 4 with different dimension symbols.

FIG. 8 is a schematic illustration showing an exemplary process ofchemical vapor deposition (CVD) for epitaxial growth of silicon on asemiconductor substrate defining at least one trenches therein in someembodiments.

FIG. 9 illustrates an exemplary pre-determined standard reference curvein accordance with some embodiments.

DETAILED DESCRIPTION

The following disclosure provides many different embodiments, orexamples, for implementing different features of the invention. Specificexamples of components and arrangements are described below to simplifythe present disclosure. These are, of course, merely examples and arenot intended to be limiting. For example, the formation of a firstfeature over or on a second feature in the description that follows mayinclude embodiments in which the first and second features are formed indirect contact, and may also include embodiments in which additionalfeatures may be formed between the first and second features, such thatthe first and second features may not be in direct contact. In addition,the present disclosure may repeat reference numerals and/or letters inthe various examples. This repetition is for the purpose of simplicityand clarity and does not in itself dictate a relationship between thevarious embodiments and/or configurations discussed.

Further, spatially relative terms, such as “beneath,” “below,” “lower,”“above,” “upper” and the like, may be used herein for ease ofdescription to describe one element or feature's relationship to anotherelement(s) or feature(s) as illustrated in the figures. The spatiallyrelative terms are intended to encompass different orientations of thedevice in use or operation in addition to the orientation depicted inthe figures. The apparatus may be otherwise oriented (rotated 90 degreesor at other orientations) and the spatially relative descriptors usedherein may likewise be interpreted accordingly.

In the present disclosure the singular forms “a,” “an,” and “the”include the plural reference, and reference to a particular numericalvalue includes at least that particular value, unless the contextclearly indicates otherwise. Thus, for example, a reference to “a nanostructure” is a reference to one or more of such structures andequivalents thereof known to those skilled in the art, and so forth.When values are expressed as approximations, by use of the antecedent“about,” it will be understood that the particular value forms anotherembodiment. As used herein, “about X” (where X is a numerical value)preferably refers to ±10% of the recited value, inclusive. For example,the phrase “about 8” preferably refers to a value of 7.2 to 8.8,inclusive; as another example, the phrase “about 8%” preferably (but notalways) refers to a value of 7.2% to 8.8%, inclusive. Where present, allranges are inclusive and combinable. For example, when a range of “1 to5” is recited, the recited range should be construed as including ranges“1 to 4”, “1 to 3”, “1-2”, “1-2 & 4-5”, “1-3 & 5”, “2-5”, and the like.In addition, when a list of alternatives is positively provided, suchlisting can be interpreted to mean that any of the alternatives may beexcluded, e.g., by a negative limitation in the claims. For example,when a range of “1 to 5” is recited, the recited range may be construedas including situations whereby any of 1, 2, 3, 4, or 5 are negativelyexcluded; thus, a recitation of “1 to 5” may be construed as “1 and 3-5,but not 2”, or simply “wherein 2 is not included.” It is intended thatany component, element, attribute, or step that is positively recitedherein may be explicitly excluded in the claims, whether suchcomponents, elements, attributes, or steps are listed as alternatives orwhether they are recited in isolation.

Referring to FIG. 1, an exemplary device 10 comprises a semiconductorsubstrate 12 and a coating layer 14 disposed on the semiconductorsubstrate 12. The semiconductor substrate 12 is a wafer comprising asemiconductor material, and optionally includes transistors and othercomponents being fabricated. Examples of suitable materials forsubstrate 12 include, but are not limited to, silicon, germanium, acompound semiconductor, and a semiconductor-on-insulator (SOI)substrate. A compound semiconductor can be an III-V semiconductorcompound such as gallium arsenide (GaAs). An SOI substrate can comprisea semiconductor on an insulator such as glass. The semiconductorsubstrate 12 can be a wafer of any size (e.g., 300 mm in diameter).

In some embodiments, the coating layer 14 may be formed through achemical vapor deposition (CVD) process using one or more gaseousprecursors, which are decomposed under heat to provide a thin layer of asolid material for the coating layer 14. In some embodiments, thecoating layer 14 comprises silicon, for example, single crystalline orpolycrystalline silicon. Epitaxial growth of silicon is achieved throughheat-activated CVD using at least one silicon-containing precursor.Examples of a suitable silicon-containing precursor include, but are notlimited to silane (SiH₄), trichlorosilane (TCS), methylsilane, disilane,trisilane, and combination thereof. A reducing reactant such as hydrogengas may be used. For example, in some embodiments, a gas stream, whichcomprises a mixture of trichlorosilane and hydrogen is introduced into aprocessing chamber, inside of which the semiconductor substrate 12 isplaced. The gas stream, after being heated, reacts to deposit silicon onthe semiconductor substrate 12. The reaction of the trichlorosilane andhydrogen may be illustrated by the following simplified formula:

SiHCl₃+H₂→Si+3HCl

In such a CVD process, the temperature can affect growth rate andmorphology of the deposited product such as silicon. For example,depending on the temperature, the resulting product may be amorphous,polycrystalline, or single crystalline silicon. The processingparameters including a setting for a targeted temperature may beempirically controlled. The actual processing temperatures are notcalibrated and controlled. The actual processing temperature may also becalibrated by measuring the thickness of the coating layer 14. However,several factors affect the thickness of the coating layer 14. Forexample, temperature and deposition time are two key factors. Accordingto the inventors' studies, temperature and deposition time may havecontribution factors in a ratio in a range of from 3:1 to 4:1. Inanother word, temperature has an effect on the thickness of the coatlayer 14 as three to four times as high as that of the deposition time.For one example, the temperature effect on the coating thickness isabout 3.6 as high as the effect of the deposition time on the coatingthickness. Overall the thickness of the coating layer 14 is verysensitive to both temperature and deposition time. The effects oftemperature and deposition time may not be effectively distinguished.

The inventors have determined the actual processing temperature insidethe processing chamber during a CVD process is one factor in determiningthe quality of the deposited product. Thus, in some embodiments, theactual processing temperature and temperature uniformity are controlledto ensure high quality of the coating layer 14 (e.g., silicon) andresulting semiconductor devices.

In accordance with various embodiments, the present disclosure providesa method for semiconductor processing, particularly a method forcalibrating and/or controlling the actual processing temperature in aCVD process, or any other coating process. The methods described inFIGS. 2A-2B are described with reference to the exemplary structuredescribed in FIGS. 3-7. In FIGS. 3-7, like items are indicated by likereference numerals, and for brevity, descriptions of the structure,provided above with reference to the preceding drawings are notrepeated.

Referring to FIG. 2A, an exemplary method 50 can be used for calibratingand/or controlling temperature in a processing chamber in accordancewith some embodiments. At process (or step) 52, a semiconductorsubstrate 102 is provided. An exemplary semiconductor substrate 102 isillustrated in FIG. 3. The semiconductor substrate 102 can be the sameas the semiconductor substrate 12 described above, except that thesemiconductor substrate 102 defines at least one first trench 106 (FIG.3) therein. The semiconductor substrate 102 can be a test piece before aprocess of fabrication of a semiconductor device, or a wafer (i.e. aworking wafer) on which semiconductor devices are built. If it is aworking wafer, the at least one first trench 106 may be near the edges.The at least one first trench 106 has side walls 105 and a bottom wall107. The at least one first trench 106 may have a first depth (d₁). Theat least one first trench 106 can be formed using any suitable method.For example, the semiconductor substrate 102 can be patterned usingphotoresist and then etched using either a wet method or a dry method(e.g., using plasma) to form the at least one first trench 106. Thedimensions of the at least one first trench 106 including the firstdepth (d₁) can be measured and recorded. In some embodiments, the atleast one first trench 106 has a width in a range of from about 5microns to about 20 microns (e.g., from 7 microns to 10 microns), andthe first depth in a range of from about 50 nanometers to about 300nanometers (e.g., from 100 nm to 200 nm).

At process 54, a coating layer 108 is deposited onto the semiconductorsubstrate 102 through chemical vapor deposition (CVD) using at least oneprecursor under a setting for a processing temperature (T). Theresulting structure 200 is illustrated in FIG. 4. The coating layer 108is the same as the coating layer 14 as described above, except the shapedue to the at least one first trench 106. In some embodiments, thecoating layer 108 comprises silicon, for example, single crystalline orpolycrystalline silicon. The coating layer 108 may fill the at least onefirst trench 106, and conformally formed above the semiconductorsubstrate 102. The coating layer 108 defines at least one second trench116 having a second depth (d₂) above the at least one first trench 106.Based on the location relative to the at least one first trench 106, thecoating layer 108 can be categorized into at least two portions,including a first portion 109 inside the at least one first trench 106,and the second portion 110 above the semiconductor substrate 102. Asillustrated in FIG. 4, the at least one second trench 116 has side walls112 and a bottom wall 114. The at least one second trench 116 may have asecond depth (d₂). The second portion 110 of the coating layer 108 alsoincludes a shoulder portion 118 above the bottom wall 114. Asillustrated in FIG. 4, the shoulder portion 118 is the portion of thecoating layer 108

In some embodiments, the coating layer 108 comprises silicon (e.g.,single crystalline) formed through epitaxial growth. Epitaxial growth ofsilicon is achieved through heat-activated CVD using at least onesilicon-containing precursor in some embodiments. The at least oneprecursor may comprise any suitable chemicals including at least onesilicon-containing precursor. For example, in some embodiments, the atleast one precursor comprises trichlorosilane (TCS) and hydrogen. TheCVD process is performed in an elevated temperature in a suitable range,for example, from about 1,000° C. to about 1,500° C. (e.g., 1,100°C.-1,200° C.). The flow rate of TCS may be in any suitable range, forexample, from about 10,000 sccm to about 20,000 sccm. Hydrogen is areactant and also a carrier gas. Gas pressure inside the processingchamber may be in any suitable range. In some embodiments, the gaspressure inside the processing chamber is about 1 atmosphere pressure.

The dimension of the at least one second trench 116 including the seconddepth (d₂) may be measured and recorded offline after the CVD process orinline during the CVD process. In some embodiments, the at least onesecond trench 116 has a width in a range of from about 5 microns toabout 20 microns (e.g., from 7 microns to 10 microns), and the seconddepth in a range of from about 50 nanometers to about 300 nanometers(e.g., from 100 nm to 200 nm). The coating layer 108 may have athickness in a range from about 5 microns to about 50 microns (e.g.,from 5 microns to about 10 microns).

The inventors have determined that processing temperature is a primaryor dominating factor in determining the second depth (d₂) of the atleast one second trench 116 relative to the first depth (d₁) of the atleast first trench 106. However, in some embodiments, to keep aconsistent temperature calibration, the coating layer 108 may bedeposited onto the semiconductor substrate 102 under the same otherconditions in each experiment. For example, the coating layer may bedeposited at a fixed gas pressure inside a processing chamber, and afixed feeding rate of the at least one precursor for a fixed period oftime.

Referring to FIG. 5, exemplary locations of trenches 106 and 116 on asemiconductor substrate 102 are illustrated. In some embodiments, thesemiconductor substrate 102 is a testing wafer (or called controlwafer), which may be recycled and reused. In some other embodiments, thesemiconductor substrate 102 may be a wafer having transistors anddevices being fabricated thereon. In either of these embodiments, the atleast one first trench 106 may be formed in any location of the wafer.For example, the at least one first trench 106 may be formed in areasclose or adjacent to the edge 210 of the semiconductor substrate 102.The at least one first trench 106 may be formed in at least two areasacross the semiconductor substrate 102 (FIG. 5), or in multiple (e.g.,3, 4, 5, or 6) locations uniformly distributed along the edge 210 of thesemiconductor substrate 102. In some embodiments, the at least one firsttrench 106 may also be formed in the middle of the semiconductorsubstrate 102. FIG. 5 only illustrates two exemplary locations for twoof the first trenches 106 and the resulting coating layer 108 having twoof the second trenches 116 above the first trenches 106. The structure200 including the semiconductor substrate 102 is projected with a viewpanel 220 having grid lines 222 for visual examination purpose only.Each respective area may be marked on the view panel 220 by at least twomarks to show the resulting coating layer 108 with a second trench 116above two of the first trenches 106.

Referring to FIG. 6, a plurality of first trenches 106, and the coatinglayer 108 having a plurality of second trenches 116, may be formed onthe semiconductor substrate 102 in some embodiments. The semiconductorsubstrate 102 can be etched to define a plurality (e.g., 2, 3, 4, 5, 6)of first trenches 106, which may be parallel to each other. Theplurality of first trenches may have similar or identical dimensionsincluding length, width and depth. For example, each of the plurality oftrenches 106 may have a width in a range of from about 5 microns toabout 20 microns (e.g., from 7 microns to 10 microns), and a depth in arange of from about 50 nanometers to about 300 nanometers (e.g., from100 nm to 200 nm). The plurality of first trenches 106 and the pluralityof second trenches 116 are used for generating a plurality data pointsfor an average value in determining actual temperatures inside theprocessing chamber.

After processes 52 and 54, the data including the first depth (d₁) andthe second depth (d₂) can be collected and treated to determine theactual processing temperature during the CVD process in process 56.

At process 56 of FIG. 2A, a depth parameter (t) of the second depth (d₂)relative to the first depth (d₁) is determined. Unless expresslyindicated otherwise, references to “a depth parameter (t) of the seconddepth (d₂) relative to the first depth (d₁)” made herein will beunderstood to encompass any relative value derived from d₁ and d₂, forexample, a difference (d₂−d₁), a ratio (d₂/d₁), or only d₂ when d₁ is afixed constant in all experiments.

In some embodiments, the depth parameter (t) is the difference betweenthe second depth (d₂) and the first depth (d₁). Alternatively, the depthparameter (t) may be represented by the second depth (d₂), wherein thefirst depth (d₁) is a fixed value.

When the depth parameter (t) is the difference between the second depth(d₂) and the first depth (d₁), such a difference also represents therelative tendency for depositing coating layer 108 above and inside theat least one first trench 106. Referring to FIG. 7, different dimensionparameters are marked. Symbol x₁ represents the thickness of substrate102 before a coating process. Symbol y₁ is the dimension from the bottomsurface of trench 106 to a bottom surface of substrate 102. Symbol x₂represents the overall thickness at the shoulder portion 118 of coatinglayer 108. Symbol y₂ is the dimension from the bottom surface of trench116 to a bottom surface of substrate 102. Symbol h₁ represents thecoating thickness of the coating layer 108 at the shoulder portion of118. Symbol h₂ represents the coating thickness of the coating layer 108at the trench portion of 109.

The relationship among these parameters can be illustrated in thefollowing equations:

d ₁ =x ₁ −y ₁

d ₂ =x ₂ −y ₂

h ₁ =x ₂ −x ₁

h ₂ =y ₂ −y ₁

t=d ₂ −d ₁=(x ₂ −y ₂)−(x ₁ −y ₁)=(x ₂ −x ₁)−(y ₂ −y ₁)=h ₁ −h ₂

Therefore, the depth parameter (t), which is the difference between thesecond depth (d₂) and the first depth (d₁), also represent thedifference between the coating thickness the shoulder portion of 118(h₁) and the coating thickness in the trench portion 109 (h₂) of thecoating layer 108.

The inventors have determined that the actual processing temperatureinside a processing chamber is the dominating factor for the depthparameter (t) of the second depth (d₂) of the at least one second trench116 relative to the first depth (d₁) of the at least first trench 106.Based on the inventors' empirical finding, the dominating effect of theactual processing temperature on the depth parameter (t) may beexplained using the schematic illustration 500 in FIG. 8.

Referring to FIG. 8, the schematic illustration 500 shows an exemplaryprocess of CVD for epitaxial growth of silicon on a semiconductorsubstrate 102 in some embodiments. When the silicon-containing precursorTCS is heated at an elevated temperature (e.g., about 1100-1200° C.),TCS reacts with hydrogen to deposit silicon. Meanwhile, the by-productHCl from the reaction between TCS and hydrogen can etch away the silicondeposited.

When the actual processing temperature is relatively low during the CVDprocess, it is harder for the by-product HCl to diffuse into the trench106, thus deposition of silicon dominates. A shallower trench 116, witha lower depth parameter (t) (i.e. d₂ relative to d₁), is produced afterthe coating layer 108 is deposited. However, when the actual processingtemperature is relatively high during the CVD process, the by-productHCl can diffuse into the trench 106 to etch the deposited silicon, thusresults in a deeper trench 116, with a greater depth parameter (t) (i.e.d₂ relative to d₁). Therefore, the depth parameter (t) (i.e. d₂ relativeto d₁) can be used to calibrate the actual processing temperature.

At process 60 of FIG. 2A, a pre-determined standard reference curve isgenerated. Process 60 is optional in the exemplary method 50. Thestandard reference curve may be established before any calibration.Process 60 may also include processes 52, 54 and 56 or the like in aprocess of establishing the standard reference curve. In someembodiments, the standard reference curve is established once as auniversal tool. The standard reference curve may be established inseveral experiments, in which each actual processing temperature ismeasured to provide the relationship between the depth parameter (t) andprocessing temperature. Process 60 is not repeated during semiconductorfabrication processes.

Referring to FIG. 2B, an exemplary method for generating apre-determined standard reference curve (process 60) may comprise twosub-processes (or sub-steps) such as 62 and 64 in accordance with someembodiments.

At process 62, a plurality of reference coating layers 108 is depositedthrough CVD using the at least one precursor at the plurality ofprocessing temperatures, which is controlled and measured. The pluralityof reference coating layers 108 have a plurality of depth parameters (t)in a first range (e.g., 50-300 nm, or 100-200 nm). The plurality ofprocessing temperatures are in the second range (e.g., 1,000-1,500° C.,1,100-1,200° C.).

At process 64, the plurality of depth parameters (t) in the first rangeis plotted as the function of the plurality of processing temperaturesto provide a standard reference curve. FIG. 9 illustrates an exemplarypre-determined standard reference curve for epitaxial growth of siliconthrough CVD using TCS and hydrogen in accordance with some embodiments.In this standard reference curve of FIG. 9, the first depth (d₁) isfixed (about 1,500 Angstroms), and the depth parameter (t) isrepresented by the second depth (d₂).

At process 70 of FIG. 2A, the processing temperature (T) in a CVDprocess at process 54 is then determined based on the pre-determinedstandard reference curve comprising a plurality of references depthparameters in the first range as a function of a plurality of referenceprocessing temperatures in a second range. In one experimental run,after a respective depth parameters (t) is obtained, the actualprocessing temperature is determined corresponding to the the respectivedepth parameter (t) on the pre-determined standard reference curve.Extrapolation of the pre-determined standard reference curve beyond thefirst and the second ranges may be optionally used. When a samplecontains a plurality of trenches 106 and 116, an average processingtemperature can be obtained. In some embodiments, the temperature atdifferent locations and a temperature distribution can be mapped outcorresponding to the semiconductor substrate 102.

At process 72, in some embodiments, the setting for temperature ischanged to adjust the actual processing temperature to a desired levelafter process 70 based on the results obtained in process 70. The actualprocessing temperature and its uniformity are adjusted to provide thedesired deposition rate and morphology of the coating layer 108 havingexcellent quality.

The present disclosure provides a method for semiconductor processing.Such a method comprises the following processes. A semiconductorsubstrate is provided. The semiconductor substrate defines at least onefirst trench therein. The at least one first trench has a first depth(d₁). A coating layer is deposited onto the semiconductor substratethrough chemical vapor deposition (CVD), for example, using at least oneprecursor under a setting for a processing temperature (T). The coatinglayer fills the at least one first trench, and defines at least onesecond trench having a second depth (d₂) above the at least one firsttrench. A depth parameter (t) of the second depth (d₂) relative to thefirst depth (d₁) is determined. The method further comprises a processof determining the processing temperature (T) based on a pre-determinedstandard reference curve comprising a plurality of references depthparameters in a first range as a function of a plurality of referenceprocessing temperatures in a second range.

In some embodiments, the coating layer comprises silicon formed throughepitaxial growth. The at least one precursor may comprise any suitablechemicals including at least one silicon-containing precursor. Forexample, in some embodiments, the at least one precursor comprisestrichlorosilane and hydrogen.

In some embodiments, the depth parameter (t) is the difference betweenthe second depth (d₂) and the first depth (d₁). Alternatively, the depthparameter (t) may be represented by the second depth (d₂), wherein thefirst depth (d₁) is a fixed value.

The method may further comprise a process of generating thepre-determined standard reference curve. In some embodiments, theprocess of generating the pre-determined standard reference curvecomprises at least two sub-steps. First, a plurality of referencecoating layers having the plurality of depth parameters in the firstrange is deposited through CVD using the at least one precursor at theplurality of processing temperatures in the second range. Second, theplurality of depth parameters in the first range is plotted as thefunction of the plurality of processing temperatures in the secondrange.

In some embodiments, the process of providing the semiconductorsubstrate defining the at least one first trench therein comprisesetching the semiconductor substrate to define a plurality of firsttrenches. In some embodiments, the at least one first trench has a widthin a range of from about 5 microns to about 20 microns (e.g., from 7microns to 10 microns), and the first depth in a range of from about 50nanometers to about 300 nanometers (e.g., from 100 nm to 200 nm).

The coating layer may be deposited onto the semiconductor substrate at afixed pressure and a fixed feeding rate of the at least one precursorfor a fixed period of time. In some embodiments, the method furthercomprises changing the setting to adjust the processing temperature to adesired level after the process of determining the processingtemperature (T) based on the pre-determined standard reference curve.

In some embodiments, a method provided in the present disclosurecomprises the following processes. A semiconductor substrate is etchedto define at least one first trench (e.g., a plurality of firsttrenches) therein. The at least one first trench has a first depth (d1).A coating layer is deposited onto the semiconductor substrate throughCVD using at least one precursor under a setting for a processingtemperature (T). The coating layer defines at least one second trenchhaving a second depth (d₂) above the at least one first trench. A depthparameter (t) of the second depth (d₂) relative to the first depth (d₁)is then calculated. The depth parameter (t) is the difference betweenthe second depth (d₂) and the first depth (d₁). The processingtemperature (T) is determined based on a pre-determined standardreference curve comprising a plurality of references depth parameters ina first range as a function of a plurality of reference processingtemperatures in a second range. The coating layer comprises siliconformed through epitaxial growth, and the at least one precursorcomprises trichlorosilane and hydrogen. In some embodiments, the coatinglayer is deposited onto the semiconductor substrate at a fixed pressureand a fixed feeding rate of the at least one precursor for a fixedperiod of time. The method may further comprise changing the setting toadjust the processing temperature to a desired level after the processof determining the processing temperature (T) based on thepre-determined standard reference curve.

In some embodiments, a method provided in the present disclosurecomprises the following processes. A semiconductor substrate is etchedto define at least one first trench (e.g., a plurality of firsttrenches) therein. The at least one first trench has a first depth (d₁).A coating layer is deposited onto the semiconductor substrate throughCVD using at least one precursor under a setting for a processingtemperature (T). The coating layer defines at least one second trenchhaving a second depth (d₂) above the at least one first trench. A depthparameter (t) of the second depth (d₂) relative to the first depth (d₁)is then determined. In some embodiments, the first depth (d₁) is a fixedvalue, and the depth parameter (t) is represented by the second depth(d₂). The method further comprises determining the processingtemperature (T) based on a pre-determined standard reference curve. Thestandard reference curve comprises a plurality of references depthparameters in a first range as a function of a plurality of referenceprocessing temperatures in a second range. The coating layer comprisessilicon formed through epitaxial growth, and the at least one precursorcomprises trichlorosilane and hydrogen. In some embodiments, the methodfurther comprises changing the setting to adjust the processingtemperature to a desired level after the process of determining theprocessing temperature (T) based on the pre-determined standardreference curve.

The methods and system described herein may be at least partiallyembodied in the form of computer-implemented processes and apparatus forpracticing those processes. The disclosed methods may also be at leastpartially embodied in the form of tangible, non-transient machinereadable storage media encoded with computer program code. The media mayinclude, for example, RAMs, ROMs, CD-ROMs, DVD-ROMs, BD-ROMs, hard diskdrives, flash memories, or any other non-transient machine-readablestorage medium, or any combination of these mediums, wherein, when thecomputer program code is loaded into and executed by a computer, thecomputer becomes an apparatus for practicing the method. The methods mayalso be at least partially embodied in the form of a computer into whichcomputer program code is loaded and/or executed, such that, the computerbecomes an apparatus for practicing the methods. When implemented on ageneral-purpose processor, the computer program code segments configurethe processor to create specific logic circuits. The methods mayalternatively be at least partially embodied in a digital signalprocessor formed of application specific integrated circuits forperforming the methods.

The foregoing outlines features of several embodiments so that thoseskilled in the art may better understand the aspects of the presentdisclosure. Those skilled in the art should appreciate that they mayreadily use the present disclosure as a basis for designing or modifyingother processes and structures for carrying out the same purposes and/orachieving the same advantages of the embodiments introduced herein.Those skilled in the art should also realize that such equivalentconstructions do not depart from the spirit and scope of the presentdisclosure, and that they may make various changes, substitutions, andalterations herein without departing from the spirit and scope of thepresent disclosure.

What is claimed is:
 1. A method, comprising: providing a semiconductorsubstrate defining at least one first trench therein, the at least onefirst trench having a first depth (d₁); depositing a coating layer ontothe semiconductor substrate using at least one precursor under a settingfor a processing temperature (T), the coating layer defining at leastone second trench having a second depth (d₂) above the at least onefirst trench; determining a depth parameter (t) of the second depth (d₂)relative to the first depth (d₁); and determining the processingtemperature (T) based on a pre-determined standard reference curvecomprising a plurality of reference depth parameters in a first range asa function of a plurality of reference processing temperatures in asecond range.
 2. The method of claim 1, wherein the depth parameter (t)is a difference between the second depth (d₂) and the first depth (d₁).3. The method of claim 1, wherein the depth parameter (t) is representedby the second depth (d₂), wherein the first depth (d₁) is a fixed value.4. The method of claim 1, further comprising: generating thepre-determined standard reference curve.
 5. The method of claim 4,wherein the generating the pre-determined standard reference curvecomprises: depositing a plurality of reference coating layers having theplurality of depth parameters in the first range using the at least oneprecursor at the plurality of processing temperatures in the secondrange; and plotting the plurality of depth parameters in the first rangeas the function of the plurality of processing temperatures in thesecond range.
 6. The method of claim 1, wherein the coating layercomprises silicon formed through epitaxial growth.
 7. The method ofclaim 1, wherein the at least one precursor comprises trichlorosilaneand hydrogen.
 8. The method of claim 1, wherein the providing thesemiconductor substrate defining the at least one first trench thereincomprises etching the semiconductor substrate to define a plurality offirst trenches.
 9. The method of claim 1, wherein the coating layer isdeposited onto the semiconductor substrate at a fixed pressure and afixed feeding rate of the at least one precursor for a fixed period oftime.
 10. The method of claim 1, wherein the at least one first trenchhas a width in a range of from about 5 microns to about 20 microns, andthe first depth in a range of from about 50 nanometers to about 300nanometers.
 11. The method of claim 1, further comprises changing thesetting to adjust the processing temperature to a desired level afterthe determining the processing temperature (T) based on thepre-determined standard reference curve.
 12. A method, comprising:etching a semiconductor substrate to define at least one first trenchtherein, the at least one first trench having a first depth (d₁);depositing a coating layer onto the semiconductor substrate using atleast one precursor under a setting for a processing temperature (T),the coating layer defining at least one second trench having a seconddepth (d₂) above the at least one first trench; calculating a depthparameter (t) of the second depth (d₂) relative to the first depth (d₁),the depth parameter (t) is a difference between the second depth (d₂)and the first depth (d₁); and determining the processing temperature (T)based on a pre-determined standard reference curve comprising aplurality of reference depth parameters in a first range as a functionof a plurality of reference processing temperatures in a second range.13. The method of claim 12, wherein the coating layer comprises siliconformed through epitaxial growth, and the at least one precursorcomprises trichlorosilane and hydrogen.
 14. The method of claim 12,wherein the semiconductor substrate is etched to define a plurality offirst trenches.
 15. The method of claim 12, wherein the coating layer isdeposited onto the semiconductor substrate at a fixed pressure and afixed feeding rate of the at least one precursor for a fixed period oftime.
 16. The method of claim 12, further comprises changing the settingto adjust the processing temperature to a desired level afterdetermining the processing temperature (T) based on the pre-determinedstandard reference curve.
 17. A method, comprising: etching asemiconductor substrate to define at least one first trench therein, theat least one first trench having a first depth (d₁); depositing acoating layer onto the semiconductor substrate using at least oneprecursor under a setting for a processing temperature (T), the coatinglayer defining at least one second trench having a second depth (d₂)above the at least one first trench; determining a depth parameter (t)of the second depth (d₂) relative to the first depth (d₁), wherein thefirst depth (d₁) is a fixed value and the depth parameter (t) isrepresented by the second depth (d₂); and determining the processingtemperature (T) based on a pre-determined standard reference curvecomprising a plurality of references depth parameters in a first rangeas a function of a plurality of reference processing temperatures in asecond range.
 18. The method of claim 17, wherein the coating layercomprises silicon formed through epitaxial growth, and the at least oneprecursor comprises trichlorosilane and hydrogen.
 19. The method ofclaim 17, wherein the semiconductor substrate is etched to define aplurality of first trenches.
 20. The method of claim 17, furthercomprises changing the setting to adjust the processing temperature to adesired level after determining the processing temperature (T) based onthe pre-determined standard reference curve.